Implantable pulse generators (IPGs) such as pacemakers and implantable cardioverter defibrillators (ICDs), which are used in the treatment of cardiac conditions, and neuromodulators or neurostimulators, which are used in chronic pain management or the actuation and control of other body systems, commonly include a housing, feedthrus, and a connector assembly that is enclosed in a header. Electrical stimulation originating in the housing is led to the connector assembly through feedthrus. The connector assembly serves to transmit electrical signals out of the IPG and to a lead electrically connected to the connector assembly, the lead transmitting electrical signals between the IPG and patient tissue.
Other implantable electronic devices such as, for example, implantable cardiac monitors (ICMs) also employ a housing and a header. ICMs are used to monitor heart function or other electrical signals, but do not administer electrotherapy.
Current header casting manufacturing processes and the associated methods of assembling the header and its enclosed connector assembly onto the housing require multiple operations, are skill intensive, and unavoidably time consuming. Connector assemblies are first cast into a header separate from the housing, the header and the connector assembly enclosed therein forming a header connector assembly. The header connector assembly is joined with the housing by injecting a thermosetting polymer (e.g., an epoxy) into an interface between the header connector assembly and the housing, such an injection process being called a backfill process. This backfill process creates attachment and electrical sealing between the header connector assembly and the housing. However, the backfill process nearly mirrors the extensive casting process used to encase the connector assembly in the header to form the header connector assembly, the backfill process involving mold set-up, mold pre-heat, epoxy dispense, epoxy curing, and mold breakdown. The backfill process is not only lengthy, but also expensive due to its many tools and equipment, and necessity for many skilled operators.
Due to the low viscosity characteristics of epoxy used in the backfill process, the epoxy has a tendency to flow into undesired areas. A common cause for rework on implantable electronic devices involves epoxy entering one or more of the lead connector receiving bores of the header connector assembly, thereby forming a barrier to the establishment of critical electrical connections between the electrical terminals of the lead connector ends and the electrical contacts of the connector assembly. Such implantable electronic device rework further extends costs and manufacturing times. Other causes for rework are experienced throughout the casting and backfill processes.
There is a need in the art for systems and methods that reduces the complexity, time, tooling and costs associated with the backfill process.